Where do ruminants (cows, sheep, etc) get their protein?


Cows feed on grass. As I understand, they actually get most of their energy from free fatty acids which are produced by their gut bacteria during fermentation of grass. So basically cows are on a high fat diet so to speak.

What I don’t quite understand is where they get the massive amounts of amino acids needed to build all of the muscle, organs, etc.

In: Biology

Grass or microbes. Plants have proteins too, and usually have all the amino acids but in varying amounts.

Some plants might have very Low amounts of lysine, but if you eat large amounts of grass you will still meet the requirements

Also, microbes can synthesize amino acids from the raw feedstock (grass). If the right mix of microbes are available there should be sufficient essential amino acids.

The ruminants eat the grass and other fibrous materials to feed the microbes in their digestive system and then the ruminants actually get their nutrition from the massive amounts of microbes at the last part of their stomach, the abomasum.

So you were right, just didn’t realize the scope of how much they actually get from those microbes.

Iirc, a significant amount of the digestive process in humans also is done by the “gut flora” (read: internal microbe population) present in all healthy humans. They live in our digestive systems, we feed them the raw materials that we’ve chewed up, and they poop out the manufactured chemicals that we need to live. We just don’t keep around the particular kinds of microbes that can make useful stuff out of grass.

It’s actually a pretty sick symbiotic system, and it blows my mind a little how complicated a process it must have been to evolve that. I think I read somewhere that, by number, we have more symbiotic microbe cells inside of us than we have cells of our own? It makes me feel torn between feeling appreciative of my little gut-bros, and mildly horrified of how what I conceive of as my own body isn’t entirely me.